Pivot



April 1953 w. H. GILLE 2,634,174

PIVOT Filed Dec. 31, 1949 3nnentol; WILLIS H. GILLE attorney PatentedApr. 7, 1953 UNITED STATES PATENT OFFICE,

Willis H. Gille, St. Paul, Minn., assignor to Minneapolis-HoneywellRegulator Company, Min,- neapolis, Minn., a corporation of DelawareApplication December 31, 1949, Serial No. 136,383

' 2 Claims. 1 This invention relates to low-friction pivots,particularly of the knife edge type.

The object of theinvention is to provide a knife edge pivot structurethat may be made on a mass production basis without the necessity foraccurate machining of the parts. The interacting parts of the pivot maybe sheet metal stampings assembled without further processing as theycome from the punch press.

In the illustrated form of the invention the composite'kni-fe edge pivotis provided-that per-- mits a limited amount of pivotal movement betweenthe parts.

Figure 1 of the drawing is an elevation of a snap switch incorporatingthe novel pivot structure.

Figure 2 is a fragmentary plan view taken substantially on line 2-2 ofFigure 1, and

Fig. 3 is a fragmentary elevation as seen from the right of Figure 1.

Other novel features of the illustrated device are covered in theapplication of Murrell F. Kautz, Serial No. 136,351, filed on December31, 1949, now Patent No. 2,582,834.

The illustrated snap switch has a base carrying a pair of terminals l iand I2. The terminal I I is connected to a'bracket l4 that carries astationary contact l5. Terminal i2 is connected to a bracket I! thatpivotally carries a switch arm I8 in a manner to be describedhereinafter. The switch arm 18 comprises an armature 20 that cooperateswith a magnet 2| to produce snap action of the switch arm. An overarm 22is secured to the right-hand end of armature 20, the relative positionsof the armature 20 and overarm 22 being adjustable by means of a screw23 as described in the above mentioned Kautz application. The

,overarm 22 carries a spring blade 24 that carries a movable contact 25adapted to coop-crate with the stationary contact l5. The movablecontact 25 and the spring blade 24 are electrically connected to thebracket H by pigtail 26.

A bracket 29 secured to the left-hand end of the base I0 carries anactuating arm 38 in a manner to permit some pivotal movement of the arm30. A push button 3| engages a spring blade 32 that is secured to theleft-hand end of the arm 30, the blade 32 providing a resilientconnection between the push button 3| and the arm 30. The blade 32serves to store energy as the push button 3! is depressed, the energybeing available to produce snap action as the armature 20 moves awayfrom the magnet 2|. A link 34 interconnects the right-hand end of thearm 38 with the right-hand end of the armature 2D to transmit forcetherebetween.

The bracketi'l is provid'edwith a pair of spaced upstanding extensionsI'la that form an angle with respect to the base of slightly less than45. Each of the extensions flu is provided with a shoulder Hb, the upperedges of the shoulders ilb being in alignment. Since the bracket I1 is asheet metal stamping it is convenient to form the shoulder lib in thesame stamping operation that forms the bracket H as a whole into itsdeveloped shape. The armature 2%] is provided with a pair of extensions20a that form an angle of slightly less than 45 with the remainder ofthe armature. Each of the extensions 20a is provided with a shoulder202), the lower edges of which are in alignment. Since the shoulder 20bis formed in the same stamping operation that forms the remainder of thearmature 20 in its developed state, the shoulder 20b forms a right anglewith the lower surface of the extension 20a.

When the switch arm i8 is placed on the bracket I! with the extension20a of the armature engaging the extension Ila of the bracket, theshoulder lib-will engage the under surface of the extension 26a and theshoulder 20b will engage the upper surface of the extension Ila. Theupper surfaces of the two extensions Ila are disposed in the same plane.Likewise the lower surfaces of the extensions 29a are disposed in thesame plane. Since the cooperating engaging edges of the shoulders Nb and2% are in alignment, a pivotal axis is established as indicated by theline A--A in Figures 2 and 3.

Pivots embodying the same principle are also employed in the pivotalconnection between the link 34 and the switch arm 13 and between thelink 3 and the arm 38. These pivotal connections also involve sheetmetal stampings that cross at an angle other than degrees. The upperend, of the link 34 is provided with a pair of shoulders 34a thatengages the under surface of an upwardly bent portion 30a OI the arm 39.The portion 33a is provided with a rectangular slot 3%, the lower outeredge of which provides a knife edge engaging the flat portion of thelink 36 intermediate the shoulders 34a. The lower end of the link 34 hasshoulders 34c having edges varm 18.

that engage the flat upper surface of an angularly disposed extension200 of the armature 20. The extension 200 of the armature has areotangular slot 20d, the outer and upper edge of which provides a knifeedge that engages link 34 intermediate the shoulders 34c. It will beseen that in each of these latter described pivotal connections threeknife edge pivots mutually cooperate to form a pivotal connectionbetween the parts. Since the knife edges are in alignment a low frictionknife edge is provided.

When the push button 3| is depressed to bias the arm 30 downwardly withsufiicient force to overcome the magnetic attraction of the magnet 2|the armature 20 and switch .arm l8 will pivot suddenly in a clockwisedirection about the axis A to a point in which the left-hand end ofoverarm 22 engages an inwardly bent portion 29a" of the bracket 29. Somepivotal movement will, of course, occur between the link 34 and the arm30 and also between the link 34 and the switch Movement will be in areverse sense when the force on the push button 3| is sufilcientlyreduced.

While the novel pivot structure has been described in connection with asnap switch it will be evident that it would find application in manyother structures where relatively friction-free pivotal movement isdesired. The scope of the invention is to be determined only by theappended claims.

I claim as my invention:

1. A pivot structure comprising a support, a pair of arms extendingoutwardly from said sup- .port, each of said arms having a fiat surfacelying in the same plane and each of said arms being notched to form ashoulder the edges of said shoulders lying in a straight line in said 4plane, a member extending between said arms and having laterallyextending portions engaging said arms, said portions having flatsurfaces lying in a common plane and engaging the edges of saidshoulders, and said portions further having shoulders with edges lyingin a straight line within the plane of the fiat surfaces of saidportions, said edges engaging the fiat surfaces of said arms. I

2. A pivot structure comprising a support, a pair of arms extendingoutwardly from said support, each of said arms having a fiat surfacelying in the same plane and each of said arms being notched to form ashoulder the edges of said shoulders lying in a straight line in saidplane, a member extending between said arms and having laterallyextending portions engaging said arms, said portions having fiatsurfaces lying in a common plane and engaging the edges of saidshoulders, and said portions further having shoulders with edges lyingin a straight line within the plane of the fiat surfaces of saidportions, said edges engaging the flat surfaces of said arms, and meanslimiting pivotal movement of said member to a range in which theforegoing relation of the parts is maintained.

WILLIS H. GILLE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name I Date 2,429,074 Rugh Oct. 14, 19472,486,061 Ransome Oct. 25, 1949 2,525,044 Puerner Oct. 10, 1950

